Weighs 2% more with battery and card, and is 66% thicker. From what I can see, the extra width comes from the admittedly stupid strap lugs on the EM5. Don't know where you got your numbers from but they're incredibly wrong.

I don't know what people's obsession is with the SL1. It's arguably the worst and most cynical of Canon's offerings. It's a worse camera than a T3i, D5100, or K-30 for more money.